@DaNi
MainActor Broadcast (MAB) for the Amiga has not been released into the public domain, so you will have to locate a copy in the 'For Sale' ads. You might try AmiBench or eBay, but MAB is very rare these days.
I use MAB a lot (visit my website for some example MAB anims). As a second alternative, the standard MainActor program was released into the pd. Its not quite as powerful as MAB (fewer file formats and no special FX) but it's still the best free animation kit for the Amiga I know of.
You can download MainActor version 1.55 from Aminet. This is the version which has appeared on various cover disks/CDs. Use the Aminet search tool and look for mainactor.lha
If you need any help with MA, I'll be pleased to offer mine. Get back by PM anytime.
Cheers,
JaX